I have, didn't hurt me much, swam competitively through high school, ind medley, freestyle, butterfly, the heardest thing I've done was try to move another athlete against his will for 6 minutes, nothing but a sprint for six minutes, pure intensity. The argument cannot be broken, too sound. I know all sports have their respective difficulties that are challenging to overcome, there also those sports which require the greatest level of physical fitness, wrestling being on top of said category. I've participated in a lot of sports, wrestling to boxing to submission grappling to tennis, track, soccer, swimming, baseball. By far, the toughest most demanding sport is the orgiinal martial art, wrestling. Football is by far my favorite sport, the sport that put me through school, free of charge. But, I respect wrestling the most, realize and understand it is truly the most demanding sport there is.